A well system, such as an oil or gas well for extracting hydrocarbon fluids from a subterranean formation, can include a multilateral wellbore. A liner assembly can be positioned in the wellbore to extend from a main bore into a lateral bore using a whipstock. The whipstock can be removed from the wellbore and cement can be used to secure the liner assembly to the wellbore. The portion of the assembly in the main bore can be drilled or washed out. A whipstock or a deflector can be positioned in the wellbore to guide tools through an inner area of the portion of the remaining liner assembly cemented at a location in the lateral bore.